Neutrino nuclear responses for double beta decays and astro neu- trinos by charge exchange reactions HIROYASU EJIRI, RCNP, Osaka Univer-

exchange reactions (CER) are shown to be used to study charged current neutrino nuclear responses associated with double beta decays(DBD)and astro neutrino interactions [1,2]. CERs to be used are high energy-resolution (He3,t) reactions at RCNP, photonuclear reactions via IAR at NewSUBARU [3] and muon capture reactions at MUSIC RCNP and MLF J-PARC. The Gamow Teller (GT) strengths studied by CERs reproduce the observed 2 neutrino DBD matrix elements [2]. The GT and spin dipole (SD) matrix elements are found to be reduced much due to the nucleon spin isospin correlations and the non-nucleonic (delta isobar) nuclear medium effects. Impacts of the reductions on the DBD matrix elements and astro neutrino interactions are discussed.